从数1ist到数函数 How many functions are there from a two-element set to a three-element set? How many functions are there from a three-element set to a two-element set? How many functions are there from a m-element set to a n-element set? T(m,n)=n*T(m-1,n) T(1,n)=n T(m,n)=nm从数list到数函数 How many functions are there from a two-element set to a three-element set? How many functions are there from a three-element set to a two-element set? How many functions are there from a m-element set to a n-element set? T(m,n)=n*T(m-1,n) … T(1,n)=n T(m,n)=n m